Wireless devices such as phones and personal digital assistants (PDAs) have become essential business and personal tools. Users are requiring more and more functionality to be supported by these devices. At the same time, users are further demanding that these devices retain or improve their speed without putting any additional drain on their limited battery power. Designers of these devices are therefore faced with two contradictory design constraints. Circuits must operate at fast speeds to meet user expectations yet these same circuits must consume less power to allow for longer battery life.
In the past, technology scaling had provided the necessary speed increases. With the advent of technology scaling, higher and higher levels of integration became possible due to the shrinking device sizes. Technology scaling was providing not only an area scaling but also a delay scaling. According to Moore's “Law”, chips were doubling their speed every 18 months. While this “law” has been applicable for more than 20 years, a point has been reached where process scaling no longer delivers the expected speed increases. This is mainly due to the fact certain device parameters have reached atomic scales. One of the consequences of this speed saturation due to technology scaling is that designers must work harder at each stage of the design flow to achieve the last remaining circuit performance. That is, even small speed/leakage-power improvements will come at significantly higher design efforts than in the past.
What is therefore needed are design tools, such as enhanced Standard Cell Libraries, that can produce circuits having optimal speed and leakage power performance.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers can indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number may identify the drawing in which the reference number first appears.